<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>document</title>
    <style>
        body {
            margin: 0;
            padding: 0;
        }
        .a1 {
            display: flex;
            border-top: 5px solid orange;
        }
        .a1 a {
            padding: 15px 20px;
            text-decoration: none;
            color: #333;
        }
        .a1 a:hover{
            color: orange;
            background-color: gainsboro;
        }
    </style>
    
</head>
<body>
    <nav class="a1">
        <a href="#">新浪导航</a>
        <a href="#">手机新浪网</a>
        <a href="#">移动客户端</a>
        <a href="#">微博</a>
        <a href="#" class="active">三个字</a>
    </nav>
</body>
</html>
